The smokeless stove

Saving the lives of African children has become a clichéd cause, thrown around so casually that it makes us cringe.

But in Dumbo, Brooklyn, in a warehouse studio with woodchips and bits of metal strewn catastrophically across the floor, a group of entrepreneurs is refining the Biolite stove, an invention designed to take out a major threat to child health in Africa today. That threat is smoke pollution from traditional cooking stoves, which is thought to be a major trigger of fatal infant pneumonia in thousands of African children each year. Since the Biolite stove dramatically cuts the smoke emissions, pollution researchers from Columbia University will soon test it in Ghana, West Africa. It will be the first and largest randomized control trial ever to study the link between cooking stove smoke and infant pneumonia. “This is a great thing to put effort into,” says one of Biolite’s inventors, Clay Burns.

The swift, feverish deaths that come with malaria and the parallel tragedy of AIDS invoke our sympathies in a way that overwhelms awareness of this other dominant threat to child health in Africa. The health problems associated with smoke pollution — low infant weight, and pneumonia — seem indirect, which also contributes to its relative anonymity. Yet the World Health Organization calls pneumonia the biggest global killer of children under 5, more so than malaria, tuberculosis, and even AIDS.

Smoke pollution in developing countries results primarily from burning biomass – wood, dung, or plant material — for cooking in enclosed spaces. In low-income settings, biomass fuel is readily available, and therefore much cheaper than fuels like gas, which we think of as ‘safer’, and which are more prominent in the West. But when pregnant mothers inhale it, damaging ingredients like carbon monoxide limit the transport of oxygen and nutrients to the womb in much the same way that cigarette smoke does. Infants are born small, light, and sickly, and so have a compromised ability to survive the first critical months of life, especially in places where poverty poses extra hurdles.

But worse, for babies just out of the womb, smoke also clogs up their airways with something known ominously as ‘black carbon’, a mix of particulate matter in the smoke that gathers deep in the lungs. This can aggravate the lungs, and lead to respiratory infection by pneumonia. In small bodies, the symptomatic cough, fever, and refusal to take a mother’s milk can overwhelm all. Pneumonia accounts for roughly 1.4 million child deaths every year, mostly in poor, rural places.

Childhood pneumonia has several causes, but cooking smoke, the WHO estimates, is what leads to at least half of those infant deaths. The new Biolite stove, by virtue of its smoke-reducing burn, should diminish — and conceivably could eradicate — this threat.

The stove itself is a 15-pound, hourglass-shaped silver appliance about the height of a human torso. It has become the glue that connects its trendy Brooklyn-based designers to a group of academics at Columbia University. The latter, who are pollution epidemiologists, have already tested versions of the Biolite stove in pilot trials on four continents, which yielded results positive enough to generate funding for the five-year long trial in Ghana, West Africa. The country’s political stability made it the easiest place to expand the project, says primary researcher Patrick Kinney, who works at Columbia’s Mailman School of Public Health.

Despite the abundance of research, no one fully understands why burning biomass can be so damaging. “It’s not really clear why pneumonia risk goes up. [It’s] sort of like the smoke is an extra burden on the lungs,” says Kinney. There’s also a challenge in understanding what actually makes up the smoke, says Darby Jack, a researcher on Kinney’s team. “No one’s really sure where the harm comes from.”

A dependable fact is that the Biolite stove decreases smokiness by 94 percent and just about eliminates black carbon: Researchers believe that if most of the smoke is gone, then the threat will go with it too, a hypothesis that will be tested in the large-scale trial.

In the Brooklyn warehouse, Clay Burns builds a hypothetical fire on the wooden floor, demonstrating why traditional cooking fires are smokier and more dangerous than his Biolite. A tall man who wears black-framed glasses and a checkered shirt, the fortuitously named Burns crouches, balancing a metal pot on top of three bricks.

In traditional set-ups like this one, he explains, plumes of smoke escape from beneath the pot, and turn the air toxic. “Fires are essentially inefficient energy users,” he says. “There’s a whole mass of messy stuff that gets shot off into the atmosphere.” But the Biolite uses “a little bit more engineering wizardry” to burn wood more efficiently, so that it releases almost no smoke. This is important because smoke indicates that some of the fuel is not being used, escaping instead in a form that incidentally harms us. No smoke means that just about all of the fuel gets burnt.

He brings out “prototype H3”, a stove used in the most recent trials. It has an orange box on one side that houses a little fan, which pumps air inside. “What that does is it inserts more oxygen into the combustion chamber,” Burns says, placing wood into the open mouth and lighting it up. The stove smokes a little, and then the burn turns clean. More oxygen and movement in a fire encourage more thorough mixing of its ingredients, which results in a stronger burn that uses up the additional gases and particles that would otherwise have escaped, he explains. This greater combustion efficiency means that those extra gases and particles do not become part of the air we breathe, and so cannot coat the insides of an infant’s lungs.

Biolite’s makers are especially proud of three features: the stove generates electric power from its own heat and it can charge a cell phone (it has a USB outlet for this); it uses half the wood that traditional fires would; and it reduces smoke by 95 percent. Thinking of a family in Ghana cooking over the stove, Burns says, “I’m pretty confident that this product will help that family.”

Still, it is the question of efficiency that drives researchers. “‘How clean is clean enough?’” says Darby Jack. One measure of cleanliness is a standard value known as pm 2.5. It measures the diameter of the particle pollutants that come from biomass fires. Particles with a diameter of 2.5 micrometers or less are more likely to get into the lungs.

“The smaller the particulate matter is, the deeper it can travel into your lungs, and the more damage it can do,” explains Niall Robinson, a climate scientist at the University of Manchester in the U.K. “Particulate matter in the deepest parts of your lungs can stay there for several weeks.”

Ideally, particle pollutants that measure pm 2.5 or less should exist only in very low concentrations in the air to reduce the likelihood of young lungs becoming intoxicated. But wood smoke is made up of more than particulate matter — so why is this ‘pm’ taken as the “gold standard,” as Kinney puts it? “What people do is pick one or two main components [of the smoke], and hope that they represent the general risk,” Kinney says, acknowledging the uncertainty. Not knowing everything about how something works, he emphasizes, is the reason why research like this needs to happen. “We don’t know anything, really, about what safe levels are, and we also don’t even know which thing to measure just to show that.” Nevertheless, the Columbia researchers believe that measuring pm 2.5, infant birth weight and lung health together, in a randomized way, will contribute to advancements in the field.

The trial in Ghana will be two-pronged. To begin with, 900 pregnant mothers spread across 177 villages will receive on-person monitors to wear, which will measure the presence of the particulate matter in outdoor air every time they cook. Some will have Biolite stoves, and others will cook with the traditional fires that they have always used. Parallel to this, researchers will assess the weight and respiratory health of each child when each of those 900 mothers gives birth. This evaluation will continue for one year after birth, largely at the hands of Columbia’s partner in the field, the local Kintampo Health Research Center, whose supervisors monitor the research by riding motorbikes to the remote villages.

The Columbia researchers haven’t mentally skipped the inherent ethical issues. Giving a potentially life-saving intervention to some but not others raises moral questions, even when saving lives is the purpose. But Kinney emphasizes that if the Biolite works, everyone who takes part in the study will get one. “We’re trying to build evidence here that shows countries that if they invested in reducing smoke produced by wood cooking, they could improve the health of mothers and infants in their country. They need the evidence, and that’s what we’re trying to produce,” Kinney says.

Ghana has two seasons: the rainy and the dry. The trial is scheduled to begin in September, on the tail end of Ghana’s wetter season. This is when Alexander Manu, a Ghanaian researcher based at the London School of Hygiene and Tropical Diseases, will return home to study the Biolite’s impact in a scattering of villages: Asantekwaa. New Longoro. Kurowuraa and Akura. Portor, Amoma and Babator. Manu says that historically, researchers treated the reduction of infant mortality like an impossible goal. “There’s been this perception that only complicated interventions can save newborns.” But this one — affordable and technically quite simple — will hopefully challenge this view.

He also voices an important motivation for the Biolite stove that gets forgotten in the face of the more immediate health concerns. The Biolite limits wood and plant fuel use by half, which means better habitat preservation; and it cuts emissions dramatically — a global climate concern, especially since black carbon is considered to be a major contributor to climate change. “Not only are we stopping the newborns from falling sick, but we are securing the environment for them,” Manu says.

Over three billion people use open cook stoves. It is a necessary evil that currently leads to an estimated two million premature deaths each year. Almost a million of those are children under five. It is an urgent problem that at this stage can be met only by the steady accumulation of evidence. “Half the world’s population is using fuels like this,” says Kinney. “It’s a very large current burden of disease, it’s a major factor for childhood pneumonia. So building a stronger evidence base for that would motivate action at the global scale.”